Connecting two blood vessels, anastomosis, is an important surgical technique for reconstructive, therapeutic and cosmetic surgery. The gold standard of anastomosis is manual suturing of the two blood vessels in a side-to-side, end-to-end or end-to-side configuration. Although it is generally desirable to shorten the length of any surgical procedure, this is especially important in coronary bypass surgery, for example minimally invasive procedures in which the heart continues beating and open surgical procedures in which a patient is often attached to a heart-lung machine and his heart is stopped.
In addition to manual suturing of blood vessels, other methods of attaching two blood vessels are known, including method using staples and anastomosis rings. PCT publications WO 97/40754 and WO 97/28749, the disclosures of which are incorporated herein by reference, describe various staplers for coronary bypass surgery, wherein a graft is connected on one of its ends to the aorta and at its other end to an occluded coronary artery, distal to the occlusion. In this type of surgery, the anastomosis is sealed by stapling the graft to the aorta, while pressing both aorta and graft against an anvil. In one publication, the anvil is inserted into the aorta for the stapling and then removed, possibly by taking the anvil apart. In the other publication, the end of the graft is everted over a ring-shaped anvil, so that the anvil is outside of the blood vessel at all times.
Recently, bypass surgery has been performed using minimally invasive (e.g., key-hole and mini-thoractomy) surgery. In this type of surgery, a small hole is made in the chest, instead of cracking open the ribs, and the mammary arteries are used for bypass grafts. The suturing and/or stapling is performed using tools, for example such as those described above.
An even less invasive type of surgery requires no opening of the chest at all. Rather, one or more catheters are introduced into the blood vessels using a percutaneous approach. PCT publications WO 97/27898, WO 97/13471 and WO 97/13463 and their priority documents, namely U.S. application 60/010,614, 60/005,164, Ser. Nos. 08/730,327 and 08/730,496, the disclosures of which are incorporated herein by reference and termed the “Transvascular Applications”, describe methods and apparatus for percutaneous treatment of arterial occlusions. Two main methods are taught in these applications. In one method, a tunnel is excavated within tissue (outside the vessel) from one side of the occlusion to the other side of the occlusion, and a stent or a stent/graft is placed within the tunnel. In another method, a conveniently located vein or graft is attached to the occluded vessel and two side-to-side anastomosis are created between the occluded vessel and the vein or graft. The distal and proximal portions of the vein are closed in one of a variety of manners. The connection between the vein and the artery may be made by welding the two blood vessels, or by using one of a variety of connectors that are suggested. One of the disclosed connectors comprises two springs separated by a short segment of a possibly unstented graft. The springs have the form of an inverted funnel, so that the two blood vessels are urged together. Where there is a spacing between the blood vessels, various techniques and/or devices are suggested for stopping the surrounding tissue from compressing the connection between the vein and the artery. One of the purposes of the various types of connectors is to maintain the two blood vessels near each-other, either in contact or compressing tissue between them, presumably so no blood will leak from the connection between the connector and the blood vessels.
In a TIPS procedure, a stent is placed into a passage percutaneously forced, opened or excavated between a portal vein and a hepatic vein. As in some of the embodiments described in the previous paragraph, the relative location of the blood vessels is maintained by the existence of relatively solid tissue surrounding and between the two blood vessels. Thus, there is no requirement that each of the connections between an end of the connector and the respective blood vessel to which it is attached, be, of itself, leak-proof.
In WWW publication “http://me210abc.stanford.edu/94–95/projects/Pfizer/Spring/1.html” (May 1998), the disclosure of which is incorporated herein by reference, a method is described for reducing the complexity of performing a bypass surgery. In this method, a graft is percutaneously brought to the aorta and pushed out of an incision in the aorta near a site of a bypass surgery. A keyhole opening is made in the chest to bring a tool to suture or staple the graft to the aorta and to the coronary which is to be bypassed.
Hinchliffe in U.S. Pat. No. 5,833,698, the disclosure of which is incorporated herein by reference, describes a multi-pin anastomosis connector, with or without a ring interconnecting the pins. Also described is a device, for attaching a graft end to a slit formed in a side blood vessel.
Rygaard in U.S. Pat. No. 5,797,934, the disclosure of which is incorporated herein by reference, describes an end-to side anastomosis device that uses a balloon inside the side artery to evert the lips of an opening in the side artery. The described anastomosis device, which is provided from outside the artery, includes releasable spikes which nail the vessels together.
Popov in U.S. Pat. No. 5,702,412, the disclosure of which is incorporated herein by reference, describes a cork-screw like head which is used to grasp a part of side artery to be punched out. Popov also describes using external clipping devices to apply clips at the circumference of the anastomosis.
Kaster in U.S. Pat. No. 4,366,819, the disclosure of which is incorporated herein by reference, describes a two part anastomotic device for end-to-side anastomosis, using an inner flange and an outer flange. When the flanges are closed an intima-to-intima contact and/or an everted graft can be formed.
PCT publication WO 98/38922, the disclosure of which is incorporated herein by reference, describes an anastomosis device formed of a flexible cord which can be formed into a loop and which has small spikes formed on it to grasp the blood vessels. Spikes can be bent back using an anvil inside the blood vessel. This device is also described as being used for end-to-end anastomosis.
PCT publication WO 98/42262, the disclosure of which is incorporated herein by reference, describes an anastomosis device that uses a plurality of needles preloaded with sutures.
Gillford in U.S. Pat. No. 5,817,113, the disclosure of which is incorporated herein by reference, describes various types of anastomosis devices including devices with bending spikes, with or without a ring (inner or outer). In some of the described devices the spikes are bent twice, each time by about 90 degrees. Another described device uses a ring which is transfixed by a plurality of hooked wires. These wires hook the “side” vessel, while the ring is connected to an “end” of a graft. When the wires are pulled, the anastomosis is closed.
Kaster in U.S. Pat. No. 5,234,447, the disclosure of which is incorporated herein by reference, describes an anastomosis device including a ring with long spikes on either side of the ring.
Snow in U.S. Pat. No. 5,797,933, the disclosure of which is incorporated herein by reference, describes an anastomosis device formed of a thin wire ring with spikes extended to one side of the ring. The ring is somewhat compressed by its having a wave profile. During deployment, the ring is straightened, increasing its radius.
Kim in U.S. Pat. Nos. 5,676,670 and 5,797,920, the disclosures of which are incorporated herein by reference, describe an anastomosis system in which a probe is inserted into a side of a blood vessel. The head of the probe is expanded to allow a mesh shaped anastomosis device to be brought into the vessel. The head is then further expanded to flatten the mesh against the inside of the blood vessel. The anastomosis is completed by applying a glue on the outside of the anastomosis.
WO 98/38941, WO 98/38942 and WO 98/38939, the disclosures of which are incorporated herein by reference, described ideas for performing transvascular bypass procedures. In one application a graft is connected from an aorta to an portion of an artery distal to its occlusion. In another, such a graft is connected from one of the vessels exiting the aorta. In another, a bypass is created by tunneling through the heart tissue.